The subject matter disclosed herein relates generally to imaging systems, and more particularly, embodiments relate to systems and methods for reconstructing medical images.
Various techniques or modalities may be used for medical imaging of, for example, portions of a patient's body. Positron Emission Tomography (PET) imaging is a non-invasive nuclear imaging technique that makes possible the study of the internal organs of a human body. PET imaging allows the physician to view the patient's entire body, producing images of many functions of the human body.
During operation of a PET imaging system, a patient is initially injected with a radiopharmaceutical that emits positrons as the radiopharmaceutical decays. The emitted positrons travel a relatively short distance before the positrons encounter an electron, at which point an annihilation event occurs whereby the electron and positron are annihilated and converted into two gamma photons each having an energy of 511 keV.
The number of coincidence events per second registered is commonly referred to as prompt coincidences or prompts. Prompts may include true, random, and scatter coincidence events. The data collected during a scan, however, may contain inconsistencies. These inconsistencies may arise from, for example, a transient interruption of communication between the detector and other portions of the imaging system. For example, a transient failure of a detector may cause a temporary loss of imaging data. The collected data is therefore corrected to account for the inconsistencies prior to using such data for reconstruction of the image.
One conventional method of correcting the collected data includes monitoring the performance of the detectors during the scan to determine if the detectors are functioning properly. If a failed detector is identified, the conventional method invalidates the data received from the failed detector over the duration of the scanning procedure. However, the failure of the detector may be transient in nature. For example, the imaging system may experience a temporary communication loss from the detector. In this case, the conventional method still invalidates the data received from the failed detector for the entire scan even though the detector may be generating valid data during a portion of the scan. As a result, the conventional method may reduce the quantity of valid data that is available to reconstruct an image. The reduction in valid data results in a reconstructed image that may have a reduced image quality compared to an image that is reconstructed using the entire set of valid data.